I would just use pvc and/flexible tubing (spa-flex) off of the return side of the pump and plumb it over the back. I found a thread online that shows how one guy did it: http://www.jeepnuts.com/reef/setup.htm
See Step 5 where he explains how he plumbed the return for his tank. Ignore how he made his sump. He didn't do such a great job there.
alright now i want to know exactly how an overflow works and what is the difference between continuous flow ones and others. and what would be a cheap one that i could get for either a 55 or 75 because i don't have 100 to shell out just on an overflow im looking more in the 50 price range